Method for preparation of vinyl silicon chlorides



Patented Dec. 5, use

METHOD, FOR PREPARATION OF VINYL SILICON CHLORIDES.

Corneille 0. Stroth'er, Buffalo, and George H. Wagner, Kenmore, N. Y.,assignors to The Linde Air Products Company, a corporation of Ohio NoDrawing. Application January 3, 1947,

Serial No. 720,108

5 Claims. (01. 260-4482) The invention relates to organosilicon compounds comprising in the molecule, a silicon atom, at least two chlorineatoms, and at least one vinyl radicle. The type formula of the compoundscontemplated by the invention is CH:==CHSliC1:

where R stands for H, C1 or CH2=CH. The particular compounds are vinylsilicontrichloride, divinyl 'silicon dichloride, andvinyl silicondichloride, CH2=CH-SiHC12. The invention includes processes andcatalyst-containing compositions for'making these compounds.- Sincevinyl silicon dichloride is a highly useful compound, and since we havefound no mention of it in the prior art, it is claimed herein as a newcomposition of matter.

Broadly speaking, the process of our invention comprises heating siliconin contact with vinyl chloride and in the presence of a catalytic metal.A number of metals are known to promote reaction between silicon andsuch organic chlorides as methyl chloride, and these metals are usefulcatalysts in our process, tin and copper being preferred.

It has been proposed to react vinyl chloride with silicon by heatingthese substances together in the presence of copper, intended to serveas a catalyst. It was stated that the reaction proceeded only with greatdiiliculty and quite small quantities of vinyl chlorosiianes wereobtained. The process was so unsatisfactory'that an indirect processinvolving the dehydrochlorination of a and ,8 chloroethyltrichorosilaneswas preferred. In contrast, we have found that by a proper choice of thesilicon-catalyst composition,

the reaction proceeds readily and with good is extracted with a suitableorganic solvent, such as acetone or ether, as illustrated by thefollowing example:

Anhydrous stannous chloride (458 grams) was intimately mixed withpowdered silicon (458 grams of 65 mesh and smaller). The mixture washeated at 350-400 C. under mm. presride.

'sure for- 13 hours. Silicon tetrachloride (77 per cent of thetheoretical quantity) was evolved according to the reaction:

The resulting mixture was extracted with acetone and dried in vacuo. Itcontained about 24 per cent of tin. The mixture was then heated at 450C. for 5 hours in a slow stream of hydrogen. In the above example thehydrogen treatment was carried out in a vertical tube of Pyrex glass, 28inches long and having an inside diameter of 2 inches. The statedquantity of material, when at rest, occupied about 20 inches of thelength of the tube. When the hydrogen treatment had been completed,vinyl chloride was passed upwardly through the mass in the same glasstube. at various rates and temperatures as shown in the following table.The rates of fiow were such that mild agitation of the silicon-tin mixwas effected.

A B C D E F Temperature, C.......... 260 400 400 475 550 Vinyl chloridefed, g./hr. 47 46 77 101 42 43 Duration, hours 14. 5 17.0 5. 5 4. 5 18.017. 2 Efliciency, weight: 1

Total product per cent.. 42 59 58 62 5o CH2=CHS1C11 ..d0.... 16.1 24. 218.3 23.0 29.3 20. 4 (CH1=CH):SiCh I (10.... 11.8 19.2 15.3 2.8 3.6 1.8Efliciency, mol: l CH7=CHS1C13 ..do.... 18. 7 28. 1 21. 2 26. 7 34. 023. 7 (CH,=CH),SiCh

1 Grams of product per gram of vinyl chloride consumed, multiplied s;the reactions 3CH =GHC1 Si CHz=CHSiCh 1 2cHF=cHoi+ Si (CH =CH)2SiGl2Each product yielded a fraction boiling below C., the boiling point ofvinyl silicon trichlo- This low-boiling fraction increasedjrom 15 percent by weight of the total product formed -at'260 C. to 43 per centwhen the reaction temperature was 550 C. About one-sixth of thelow-boiling material was the new compound vinyl silicon dichloride,having an uncorrected boiling point of 66.5 C. and the following anaysis. (The numbers in parenthesis are the theoretical values forCH2=CHSiHC12.)

Carbon 17.6% (18.9) Hydrogen 3.1% (3.2) Chlorine 56.7% (55.6)

A determination of the degree of unsaturation indicated 1.1 double bondspermolecule.

What is claimed h:

1. Process of preparing vinyl silicon chlorides which comprises reactingsilicon with stannous chloride to reduce the latter and thereby producea mix containing silicon and tin, and reacting said mix with vinylchloride.

2. Process of preparing vinyl silicon chlorides which comprises reactingsilicon with a chloride of a catalytic metal or the grou consisting ofcopper and tin to reduce the chloride and thereby l0 produce a mixcontaining silicon and catalytic metal, extracting residual chloridefrom said mix, and reacting said mix with vinyl chloride.

3. Process of preparing vinyl silicon chlorides which comprises reactingsilicon with stannous is chloride to reduce the latter and therebyproduce a mix containing silicon and tin. extracting residual chloridefrom said mix, and reacting said mix with vinyl chloride.

4. Process oi preparing-vinyl silicon chlorides go which comprisesreacting silicon with a chloride 01' a catalytic metal 0! the groupconsisting of copper and tin to reduce the chloride and thereby producea mix containing silicon and catalytic metal. extracting residualchloride from said mix, and heating said mix at a temperature above 200C. in contact with vinyl chloride.

5. Process 01 preparing vinyl silicon chlorides which comprises reactingsilicon with stannous chloride to reduce the latter and thereby producea mix containing silicon and tin, and heating said mix at a temperatureabove 200 C. in contact with vinyl chloride.

CORNEIIIE O. STRUIHER. GEORGE H. WAGNER.

REFERENCES CITED 'The following references are of record in the tile ofthis patent:

UNITED STATES PATENTS OTHER REFERENCES Hurd: Jour. Amer. Chem. Boc.,vol. 67 (1945), pages 1813-14; s 4.

1. PROCESS OF PREPARING VINYL SILICON CHLORIDES WHICH COMPRISES REACTINGSILICON WITH STANNOUS CHLORIDE TO REDUCE THE LATTER AND THEREBY PRODUCEA MIX CONTAINING SILICON AND TIN, AND REACTING SAID MIX WITH VINYLCHLORIDE.